1. Field of the Invention
The present invention generally relates to an apparatus for selectively extending and retracting a utility line, hose, or the like. More particularly, the present invention relates to an apparatus for selectively extending a dental utility line for utility line use and selectively retracting a dental utility line for utility line storage.
2. Description of the Prior Art
The prior art is replete with examples of apparatus and systems for enabling users to selectively extend and retract a utility line, hose, or cord. The dental industry, in particular, requires utility lines for the actuated use of a variety of dental instruments and appliances and thus has been offered a variety of means for selectively extending and selectively retracting utility lines in the office. It has been noted that when an effective dental utility line storage system (that enables the user to selectively extend a line for use and selectively retract a line for storage) is not employed in a dental practice setting, the dental utility lines often become entangled with one another or damaged by everyday office behavior, such as by being trampled under foot or by rolling chairs and the like. Added to the potential for damage and entanglement is the rather unsightly appearance of utility lines. Dental practitioners typically strive to enhance the appeal of their offices since the services they perform can often be rather unpleasant and thus a means for storing utility lines behind the scenes is preferable to allowing utility lines to be open for unsightly inspection. The prior art thus teaches a variety of devices or systems to effectively store dental utility lines and allow selective extension and retraction thereof for generally enhancing the dental office visit. Some of the more pertinent prior art relating to these subjects is described hereinafter.
U.S. Pat. No. 3,180,585 ('585 Patent), which issued to Pusey et al., discloses an Extendable and Retractable Utility Line Apparatus. The '585 Patent teaches an extendable utility line apparatus providing automatic retraction for an extended line. The extendable utility line apparatus comprises a console cabinet having a hinged cover, a series of broad and relatively shallow structural channels of smooth-faced material removably mounted in the cabinet and disposed back to open mouth so as to define a corresponding series of vertically disposed and elongate smooth-wall pockets. The upper end of the back of each channel projects upwardly beyond its sides. A bottom grooved spanning board is slidably mounted within the cabinet and normally extends across the upper ends and slidably receives the end within its grooves for firmly positioning the channels within the cabinet. A utility line for each pocket extends into the upper end of the pocket, dipping low into the pocket in retracted position and looping back to return to the upper end of the pocket to emerge therefrom and extend through the hinged cover. Further disclosed are means for supporting the emergent upper end of the retracted utility line against being withdrawn through the cover and into the pocket. A freely floating sheave, having no connection with the pocket-defining structure, is disposed within the loop of the utility line for riding upwardly in the pocket with the loop as a guide and retainer when the utility line is extended, and for dropping down with the loop when the line is released. The line thus retracts automatically under the influence of gravity, the sheave having sound absorbent material laterally thereof as a silencer.
U.S. Pat. No. 3,427,719 ('719 Patent), which issued to Gordon et al., discloses a Dental Unit. The '719 Patent teaches a dental instrument unit comprising in combination an extendable utility line having a dental instrument thereon, the extendable utility line being anchored within a cabinet and being trained over a pulley on a movable piston within the cabinet. Further the line is trained over a fixed pulley to extend outside of the cabinet. Vacuum means may be applied to the piston to retract the utility line.
U.S. Pat. No. 3,429,516 ('516 Patent), which issued to Sharp et al., discloses Dental Equipment. The '516 Patent teaches a support for dental equipment of the type that has a flexible hose connected at one end with an instrument and at the opposite end with a hose activation or actuation means. The hose is suspended in a loop between a pair of upright guides. A weighted pulley rides in the loop of the hose and is supported by the upright guides. The pulley assembly applies tension to the hose to draw the instrument end of the hose into the cabinet where the support is mounted. The instrument end of the hose passes through a tube at the top of the cabinet and the outer end of the tube supports the instrument in position for being grasped by the user. A catch mechanism on the pulley assembly latches the pulley assembly temporarily at the top of the guides to relive the tension in the hose. The catch may be readily unlatched by pulling on the instrument end of the hose. The weight of the pulley assembly then draws the instrument end of the hose into the cabinet.
U.S. Pat. No. 3,793,729 ('729 Patent), which issued to Nyboer, discloses a Gripping Device Assembly for Tensioned Pliable Elongate Member. The '729 Patent teaches an assembly used in conjunction with a hand-holdable instrument that has an elongate pliable member extending therefrom to a source of power that serves to actuate the instrument. The assembly comprises a housing that is located in a fixed base position relative to the source of power, and the housing having the elongate pliable member extending therein. The confined space is partially defined in the housing by a top and bottom, with the bottom including an inclined surface on which a rotatable member is movably supported. Means for maintaining tension on the elongate pliable member are disposed between the source of power and the housing.
The housing is preferably capable of removably supporting the instrument at a first position thereon. When the instrument is moved outwardly from the housing without the pliable elongate member contacting the rotatable member, tension is maintained on the elongate member until the instrument is moved downwardly to bring the elongate member into friction contact with the rotatable member. The instrument is then allowed to move toward the housing a short distance due to the tension on the elongate member, with the rotatable member now rolling up the inclined surface to frictionally grip the pliable elongate member between the rotatable member and the top of the housing. The portion of the elongate member extending outwardly from the housing to the instrument is now free of tension and the instrument may be maneuvered without any restraint thereon. After the instrument has been used, the instrument is returned to the first position by reversing the above-described steps.
U.S. Pat. No. 5,450,874 ('874 Patent), which issued to Hamula, discloses a Dental Instrument Hose Retraction Device. The '874 Patent teaches a device for retracting and storing a length of hose. The device is housed within a dental cabinet and includes a rectangular compartment formed by integral side walls and front and rear walls. A plurality of spool supports is positioned adjacent to the side walls. A spool is positionable within the compartment. A length of hose anchored at the rear wall is routed under the spool and through an opening in an instrument panel of the dental cabinet. At the distal end of the hose is attached the desired dental tool. In retracted position, the hose hangs in a loop or bight with the spool supported on the bight. The weight of the spool normally keeps the hose under tension. The device is operated by pulling on the distal end of the hose such that the spool is lifted onto and secured by the spool supports. In this position, tension is released from the hose. The hose is retractable by exerting a quick jerk or pull on the distal end of the hose which dislodges the spool from the spool support causing the spool to displace vertically down into the compartment, exerting a downward force on the hose to retract it.
It will thus be noted that the prior art teaches a variety of mechanisms for allowing dental practitioners to both store a plurality of utility lines and further to selectively extend and retract each of the utility lines for operative use. It will be noted that a variety of pulley assemblies have been developed to enhance the effectiveness of the utility line extension and retraction systems. Further, the prior art teaches a variety of means for braking the utility line when in a fully extended, operative state. A number of retraction means are also taught by the prior art. From a thorough inspection of the prior art, it will be seen, however, that none of the prior art teach a uniquely configured traveling pulley assembly track comprising an ascension path for utility line extensions and a separate and distinct descension path for utility line retractions.
Further, it is noted that prior art braking systems employing line-cinching or line-pinching means for braking the utility line are deficient for various reasons. In this regard, it has been noted that cinch or pinch-type braking means, which attempt to hold utility lines in an extended state for utility line use often fail to properly grab or hold the utility line in place for utility line use. See, for example, the '729 Patent. Cross sectional configurations of utility lines vary in practice, there being a number of different types of utility lines for actuating different types of dental instruments. These utility lines often rotate about the axis extending therethrough and thus means for cinching or pinching the line in place often fail to properly make sufficient frictional contact with the utility line for holding the same in place. Further, these systems may compromise the effectiveness of the utility line by kinking the line or by damaging the line from repeated pinched engagement. Thus, it is contemplated that braking systems that do not rely upon line-cinching or line-pinching braking means are to be preferred over those that do.
While the '874 Patent teaches braking means that do not comprise line-cinching or line-pinching means for braking a utility line, the '874 Patent does not teach a positive tracking system with transitional lock or transitional brake means. It will be seen from an inspection of the '874 Patent that the hose is retractable by exerting a quick jerk or pull on the distal end of the hose which dislodges the spool from the spool support causing the spool to displace vertically down into the compartment, exerting a downward force on the hose to retract it.
From a review of the above-referenced patents and other prior art generally known to exist, it will be seen that the prior art does not teach a positive tracking system, comprising a closed path with transitional braking means along the closed path. It will be further seen that the prior art does not teach a selectively extendable and selectively retractable utility line system comprising non-frictional braking means. The prior art thus perceives a need for a selectively extendable and selectively retractable utility line system comprising positive tracking with smooth transitional brake means for enhancing utility line extensions and utility line retractions.